Grinding heads



1956 w. E. MCAFEE GRINDING HEADS Filed Aug. 28, 1953 IN V EN TOR. MAL rap 5 /7c Ara United States Patent Machine Company, Orange, Mass, a corporation of Massachusetts Application August 28, 1953, Serial No. 377,168 6 Claims. (Cl. 51-497) This invention relates to valve grinding machines and more particularly relates to the grinding heads thereof.

One object of this invention is an improved grinding head whose grinding surfaces are readily replaceable. To attain this object provision is made that the grinding surfaces be removably attachable to the grinding head.

Another object of this invention is the interposition of yieldable backing material between the grinding surfaces and the grinding head. The yieldable backing is permanently attached to the grinding head to attain some of the advantages to be hereinafter pointed out. To attain still other advantages to be hereinafter pointed out, provision is made that the yieldable backing material be removably attached to the grinding head.

Another object of this invention is an improved grind ing head whereby chattering is reduced to a minimum. To attain this object the grinding head is provided with a grinding surface along its working plane which is less than the surface of the grinding head at the working plane. Preferably, the grinding surface is an interrupted surface forming grinding sections which are spaced equidistant from each other. In the embodiment shown, the grinding head comprises a disk having raised portions upon which the grinding surfaces are located and the raised portions are spaced from each other for an angular disstance greater than the width of each grinding surface.

The accompanying drawings illustrate the preferred forms of my invention and show the invention as applied to a valve grinding head particularly adapted to grind gate valves and the specific details shown in the drawing are for that particular type of grinding head. In the drawings:

Fig. l is a plan view of the grinding head used with my invention;

Fig. 2 is a sectional side elevation taken on line II--II of Fig. 1;

Fig. 3 is a sectional side elevation taken on line III-III of Fig. 1;

Fig. 4 is a view similar to Fig. 3 showing one embodiment of the invention; and

Fig. 5 is a view similar to Fig. 3 showing another embodiment of the invention.

The disk 1 has a central hole 3 therein for attachment on the shaft 5 (shown in dotted lines) which is driven by the machine (partly shown in dotted lines at 7 in Fig. 2). The attachment of the disk 1 onto the shaft 5 may be realized in any desired or conventional manner, such as by applying the retaining ring9 (shown in dotted line in Fig. 2) on the shaft 5 in the central depression 11 of the disk 1.

The disk 1 has the raised portions 20 integral with each other at the center of the disk and separated from each other by the depressed portions 22. The raised portions 20 are equidistant from each other and are spaced from each other for an angular distance greater than the width of each raised portion. In the drawing the raised portions are shown as spaced at 120 angles from each other.

- or less of these raised ice It will be understood, of course, that there may be more portions 20 than the three shown, as may be desired.

Each of the raised portions 20 are provided with a.

grinding surface 26 adjacent to the perimeter of the disk l at its Working plane 24 which, in the present instant, 22. Each grinding: surface is in the form of the grinding strip 26 having an is parallel to the depressed portion abrasive on the working face.

Each strip 26 is shown as removably attached to each' attachment may be accomplished in any In the drawings, the strip 26 is attached to the raised portion 20 by tightening clamps: 28 on the strip 26 in the depressed portions 22 on each:

portion 20. The

known or desired manner.

side of the raised portion 20 by meansof screws 30.

Yieldable backing material 32, such as rubber or plastie, is interposed between each raised portion 20 and the strip 26 on the working plane 24 of the raised portion 20. This backing material 32 may be permanently attached to the working plane 24 of the raised portion 20 (as shown in Fig. 4), or may be permanently attached to the strip 26 and be placed on the raised portion 20 (as shown in Fig. 5). The advantage attained by using the embodiment of Fig. 5 is that a fresh yieldable backing piece is placed on each raised portion 20 every time the grinding strip 26 is replaced. The advantage attained by using the embodiment of Fig. 4 is that it is more economical.

In operation, the disk is assembled on the shaft 5 by placing the shaft 5 in the hole 3 of the disk 1 and clamping the ring 9 into the shaft 5. The strips 26 are assembled on the raised portions 20 by tucking the ends 27 of the strips 26, under the clamps 28, and tighening the screws 30. Of course, the mounting of the strips 26 may be accomplished before the disk is assembled on the shaft 5, if desired.

The disk 1 then is operated by the shaft 5. The working plane 24 of the disk 1 faces the gate valve seat 40 to be ground (shown in dotted lines) and the grinding surfaces 26 grind the valve.

When the grinding surfaces are worn out, the screws 39 are unscrewed, the clamps 28 lifted, and the strips 26 are discarded. New strips are then placed on the raised portions .24), without dismantling the disk 1, as pointed out above.

It will be observed that this arrangement permits the grinding surfaces to be replaced quickly, cheaply, and conveniently, and it eliminates chattering because of the spaced grinding surfaces.

I claim:

1. A grinding head fora valve grinding machine com prising a disk adapted to be mounted on said machine,v

raised portions on said disk, each of said raised portions:

having side walls and a surface in the working plane and being spaced from each other by depressed portions, said working plane being parallel to said depressed portions. and separable grinding surfaces presented in the Working plane and positioned intermediate dependent of and material mounted in said depressed area, said grinding, surfaces being longer than said resilient material and.

each having its end portions bent downwardly and en gaged with the side walls.

2. A grinding head as set forth in claim 1, wherein each other at the said disk comprising a central core mountable on a driving shaft for rotation therewith, a grinding sections.

Patented Aug. 7, 1956 p of said raised portions. of the disk, said grinding surfaces being separate and in spaced from each other and a resilient:

extending outwardly from and immovably aff xed to the central core, said grinding section being defined by opposed side walls and an end face presented in the working plane. and a relatively thin, flexible separahly formed replaceable abrasive strip having,- extension portions at its opposite ends bent rearwardly to embrace the side walls of the section to hold the intermediate portion of the strip in superimposed relation to said face and a yieldable cushion interposed between said face and said intermediate portion of the abrasive strip.

5. A grinding head as set forth in claim 1 wherein the cushion is fixedly attached to said face of the grinding section.

6. A grinding disk for a globe valve grinding machine, said disk comprising a central core mountable on a driving shaft for rotation therewith, a plurality of grinding sections extending outwardly from and immovably afiixed to the central core, each of said grinding sections being defined byv opposedv side walls and an outermost face presented in the working plane each section having associated therewith a relatively thin, flexible, separably formed replaceable abrasive strip having extension portions at its opposite ends, bent rearwardly to embrace the side walls of the section to hold the intermediate portion of the strip in superimposed relation to said end face, and a yieldable cushion interposed between said end face and said intermediate portion of the abrasive strip.

References Cited in the file of this patent UNITED STATES PATENTS 

